I. Field of the Invention
The present invention relates to data communication. More particularly, the present invention relates to novel and improved techniques for multiplexing high-speed packet data transmission with conventional voice/data transmission in a wireless communication system.
II. Description of the Related Art
A modern day communication system is required to support a variety of applications. One such communication system is a code division multiple access (CDMA) system that supports voice and data communication between users over a terrestrial link. The use of CDMA techniques in a multiple access communication system is disclosed in U.S. Pat. No. 4,901,307, entitled xe2x80x9cSPREAD SPECTRUM MULTIPLE ACCESS COMMUNICATION SYSTEM USING SATELLITE OR TERRESTRIAL REPEATERS,xe2x80x9d and U.S. Pat. No. 5,103,459, entitled xe2x80x9cSYSTEM AND METHOD FOR GENERATING WAVEFORMS IN A CDMA CELLULAR TELEPHONE SYSTEM.xe2x80x9d A specific CDMA system is disclosed in U.S. patent application Ser. No. 08/963,386, entitled xe2x80x9cMETHOD AND APPARATUS FOR HIGH RATE PACKET DATA TRANSMISSION,xe2x80x9d filed Nov. 3, 1997 (the HDR system), now U.S. Pat. No. 6,574,211, issued Jun. 3, 2003. These patents and patent application are assigned to the assignee of the present invention and incorporated herein by reference.
CDMA systems are typically designed to conform to one or more standards. Such standards include the xe2x80x9cTIA/EIA/IS-95-B Mobile Station-Base Station Compatibility Standard for Dual-Mode Wideband Spread Spectrum Cellular Systemxe2x80x9d (the IS-95 standard), the xe2x80x9cTIA/EIA/IS-98 Recommended Minimum Standard for Dual-Mode Wideband Spread Spectrum Cellular Mobile Stationxe2x80x9d (the IS-98 standard), the standard offered by a consortium named xe2x80x9c3rd Generation Partnership Projectxe2x80x9d (3GPP) and embodied in a set of documents including Document Nos. 3G TS 25.211, 3G TS 25.212, 3G TS 25.213, and 3G TS 25.214 (the W-CDMA standard), the xe2x80x9cTR-45.5 Physical Layer Standard for cdma2000 Spread Spectrum Systemsxe2x80x9d (the cdma2000 standard), and the xe2x80x9cTIA/EIA/IS-856 cdma2000 High Rate Packet Data Air Interface Specificationxe2x80x9d (the HDR standard). New CDMA standards are continually proposed and adopted for use. These CDMA standards are incorporated herein by reference.
Some CDMA systems are capable of supporting multiple types of service (e.g., voice, packet data, and so on) over the forward and reverse links. Each type of service is typically characterized by a particular set of requirements, some of which are described below.
Voice service typically requires a fixed and common grade of service (GOS) for all users as well as (relatively) stringent and fixed delays. For example, the overall one-way delay of speech frames may be specified to be less than 100 msec. These requirements may be satisfied by providing a fixed (and guaranteed) data rate for each user (e.g., via a dedicated channel assigned to the user for the duration of a communication session) and ensuring a maximum (tolerable) error rate for speech frames independent of the link resources. To maintain the required error rate at any given data rate, higher allocation of resources is required for a user having a degraded link.
In contrast, packet data service may be able to tolerate different GOS for different users and may further be able to tolerate variable amounts of delays. The GOS of a data service is typically defined as the total delay incurred in the error free transfer of a data message. The transmission delay can be a parameter used to optimize the efficiency of a data communication system.
To support both types of service, a CDMA system can be designed and operated to first allocate transmit power to voice users requiring a particular GOS and shorter delays. Any remaining available transmit power can then be allocated to packet data users whom can tolerate longer delays.
In the CDMA system, each transmission source acts as interference to other transmission sources. Because of the bursty nature of packet data, the transmit power from a transmission source can fluctuate widely during the transmission of data bursts. The rapid and wide fluctuation in the transmit power can interfere with other transmissions from other sources and can degrade the performance of these transmissions.
As can be seen, techniques that can be used to efficiently and effectively multiplex high-speed packet data transmissions with voice and other transmissions are highly desirable.
The present invention provides various techniques for supporting voice/data and high-speed packet data services concurrently and to minimize the impact of packet data service on voice/data service. In accordance with an aspect of the invention, voice/data and packet data can be multiplexed within a transmission interval (e.g., a slot) such that the available resources are efficiently utilized. In accordance with another aspect of the invention, the transmit power from a base station is controlled such that the amount of variation in the total transmit power is maintained within a particular range to reduce degradation to transmissions from this and other transmission sources (e.g., base stations).
A specific embodiment of the invention provides a method for concurrently transmitting a number of types of data in a wireless (e.g., CDMA) communication system. In accordance with the method, a first type of data (e.g., voice, overhead, low and medium rate data, delay sensitive data, signaling, and so on) is received and processed in accordance with a first signal processing scheme to generate a first payload. A second type of data (e.g., high-speed packet data) is also received and processed in accordance with a second signal processing scheme to generate a second payload. The first signal processing scheme can conform to, for example, the W-CDMA or cdma2000 standard, and the second signal processing scheme can implement, for example, the HDR design.
First and second partitions are then defined in a transmission interval, with the first partition being used to send the first type of data and the second partition being used to send the second type of data. The first and second payloads are then multiplexed onto the first and second partitions, respectively, and the multiplexed first and second payloads are transmitted. The capacity for the transmission interval can be selected to be greater than that required by the first payload (e.g., by using a shorter length channelization code)
The invention further provides other methods, transmitter units (e.g., base stations), receiver units (e.g., remote terminals), and other elements that implement various aspects, embodiments, and features of the invention, as described in further detail below.